System for cutting the cornea of an eye

ABSTRACT

A system for cutting the cornea of an eye, includes a moveable member with a cutting blade at one end, a pivot element and a cutting guide restraint. A mechanism for oscillating the moveable member around the pivot element and a cutting guide are configured to engage the cutting guide restraint on the moveable member and thereby limit the degree of angular movement of the cutting blade as the moveable member oscillates about the pivot element. A positioning system is configured to advance the moveable member with respect to the cutting guide such that the shape of the cutting guide determines the shape of a cut made by the cutting blade. A suction ring for stabilizing the cornea and an applanating plate for flattening the cornea usually complete the system.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 10/445,065 (Attorney Docket No. 022253-000100US),filed May 27, 2003, the full disclosure of which is incorporated hereinby reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to surgical systems for cutting thecornea of a patient's eye.

[0003] The cornea is the clear cover of the eye and is also the mainfocusing lens in the eye. Disorders of the cornea, which adverselyaffect its shape or clarity, can cause loss of vision. Such disordersinclude Fuchs' endothelial dystrophy, pseudophakic bullous keratopathy,keratoconus, and herpes virus infection. When these conditions aresevere the most common treatment is a full thickness corneal transplantwhich is also known as penetrating keratoplasty.

[0004] Penetrating keratoplasty is the removal of a full-thickness diskof diseased corneal tissue followed by the replacement of the diseasedfull-thickness disk of tissue by a full thickness disk of donatedhealthy corneal tissue. Currently, the diseased tissue is removed by theuse of a non-automated or automated corneal trephine combined withmanual excision using scalpels and or micro-surgical scissors. The diskof donated healthy corneal tissue is then secured to the recipientcornea by the means of sutures using micro-surgical techniques.Penetrating keratoplasty can provide dramatic improvements in vision inpatients who have opacified or irregularly shaped corneas.Approximately, 40,000 corneal transplants are performed annually in theUnited States.

[0005] However, there are distinct disadvantages of penetratingkeratoplasty. For example, penetrating keratoplasty has a long recoverytime and typically takes between 6 to 12 months to achieve good vision.Moreover, because the donor corneal tissue is sutured manually, even inthe hands of an experienced corneal surgeon, irregularities in the shapeof the cornea frequently occur and can produce decreased vision becauseof induced astigmatism. The donated corneal tissue can also be rejectedby the recipient's immune system with resulting loss of transparency ofthe donated cornea. Penetrating keratoplasty also has the potential fora devastating complication called expulsive suprachoroidal hemorrhage.In this complication, a spontaneous hemorrhage from the choroidal bloodvessels behind the retina can occur during penetrating keratoplastysurgery after the diseased cornea has been removed and before the donorcornea has been sutured securely in place. Because the eye is open toatmospheric pressure in this situation, there is no normal intraocularpressure to stop the choroidal vessels from bleeding. The terribleresult is that the retina, vitreous, and crystalline lens may beexpulsed from the opening in the cornea resulting in blindness. Thiscomplication is estimated to occur approximately 1 in 500 cases withpenetrating keratoplasty. Endophthalmitis (i.e. infection of the insideof the eye) is another serious complication that can occur and can alsocause blindness if treatment is unsuccessful. Finally, after penetratingkeratoplasty, the eye is very sensitive to injury, since the junction ofthe transplanted cornea and the recipient cornea can be easily disruptedwith even mild trauma.

[0006] Because of the disadvantages of penetrating keratoplasty othermethods of corneal surgery have recently been developed, as follows.

[0007] Lamellar keratoplasty is the general term for corneal surgeriesthat involve cutting within the layers (lamellae) of the cornea.Lamellar keratoplasty techniques allow removal and replacement ofspecific layers of the cornea. It is useful to be able to remove andtransplant specific layers of the cornea because there are commoncorneal conditions that involve only certain layers of the cornea.

[0008] For example, a scar in the cornea from a herpes virus infectionmay affect only the superficial layers of the cornea. Removal andtransplantation of the superficial layers of the cornea may be all thatis necessary to restore sight to an eye that has a superficial scar andavoids many of the complications that can be associated with penetratingkeratoplasty including endophthalmitis and expulsive suprachoroidalhemorrhage.

[0009] Another example would be Fuchs' endothelial dystrophy. Theendothelium is the innermost layer of the cornea, which is responsiblefor pumping fluid out of the corneal tissues. This removal of fluidprevents the cornea from swelling and becoming opaque. In Fuchs'endothelial dystrophy, the endothelium is damaged and is unable toadequately pump fluid out of the cornea, which results in swelling andopacification of the cornea. Removal of the diseased inner layers of thecornea and transplantation with a layer of healthy tissue can restoreclarity to the cornea and vision to the eye. By only exchanging theinner layers of tissue, the front surface of the cornea is essentiallyundisturbed. This decreases the likelihood of post-surgical astigmatismand may also result in less risk of rejection of the transplantedtissue.

[0010] A particular technique of lamellar keratoplasty is anteriorlamellar keratoplasty. Anterior lamellar keratoplasty is a procedurewhere the superficial layers of the cornea are separated from the deeperlayers with a hand held scalpel or an automated corneal surgical devicecalled a microkeratome. Using this technique, a cap of the superficiallayers of the cornea is removed and then replaced with a healthy capfrom the superficial layers of the donor cornea.

[0011] Unfortunately, corneal tissue removal and replacement by the freehand method is extremely difficult to perform. Under the best ofcircumstances, it usually results in irregular astigmatism that iscaused by irregularities in the thickness of the corneal tissue removedas well as in the thickness of the transplanted tissue. The irregularastigmatism typically limits the best spectacle corrected vision to nobetter than 20/40.

[0012] As stated above, automated anterior lamellar keratoplastyinvolves the excision of a cap of superficial corneal tissue by the useof a microkeratome. Similarly, the same apparatus can be used to preparea cap of superficial donor corneal tissue for transplantation. The donortissue is then sutured to the recipient cornea. The sutures aretypically removed within the first few months to minimize astigmatism.Unfortunately, a problem that can occur with this technique is that thetransplanted donor disk may be dislodged with relatively minor trauma,even after prolonged periods of time. This can occur because the cap ofcorneal tissue is only held in place by the relatively weak healingbetween the layers of donor and recipient tissue and there is no supportagainst lateral or vertical pressure.

[0013] Another particular technique of lamellar keratoplasty isposterior lamellar keratoplasty. Posterior lamellar keratoplasty is aprocedure where the deeper (i.e. rear) layers of the cornea areseparated from the superficial layers with a hand held scalpel or anautomated microkeratome. A disk of the deeper layers of the cornea isremoved and then replaced with a healthy disk from the deeper layers ofthe donor cornea.

[0014] In the free hand posterior lamellar keratoplasty technique, ablade is manually used to create a pocket in the deep layers of thecornea. An internal manual trephine is then used to cut a disk of thedeepest corneal layers. The disk of the deepest corneal layers is thenexcised with microsurgical scissors and or scalpels.

[0015] The donor corneal disk of the deepest corneal layers is thenharvested by one of three methods.

[0016] In a first method a fresh whole donor eye is pressurized withbalanced salt solution and a free hand dissection is used to create apocket within the deep layers of the cornea. The donor disk of thedeepest corneal layers is then excised with a trephine, microsurgicalscissors, or scalpels. Difficulties with this method include theextremely tedious and difficult nature of the surgical dissection, thepotential for inadvertently destroying the donor disk as part of thedissection, and the difficulty with finding a fresh human cadavericdonor eye that is available for surgery within 48 hours of the donor'stime of death. Unlike excised donor corneas, whole donor eyes lose theirviability to be used as donor tissue within 48 hours.

[0017] In a second method, a donor cornea and attached scleral rim isplaced within a free standing anterior chamber maintainer. The donorcornea is then pressurized to maintain rigidity of the corneal tissue. Afree hand dissection then ensues to create a partial thickness cornea ofthe deepest layers only. The disk of tissue is then excised using atrephine. Again, a significant problem with this method of harvestingdonor tissue is that the free hand dissection is difficult and timeconsuming. There is also the risk of damaging the donor tissue throughthe dissection that renders it useless for transplantation.

[0018] In a third method, the donor cornea and attached scleral rim areplaced within a free standing anterior chamber maintainer. The donorcornea is then pressurized to maintain rigidity of the corneal tissue. Aseparate prior art flap or cap making microkeratome that is adapted foruse with the anterior chamber maintainer is used to create a flap or capin the donor tissue. A disk of tissue is then excised from the partialthickness layers of the cornea that were created by the microkeratome.The primary problem with this method is that a separate prior artexpensive flap or cap making microkeratome device is required to harvestthe corneal tissue. Moreover, the flap or cap making microkeratomecannot be used to create the corneal pocket.

[0019] Once the disk of the deepest corneal layers is harvested, it isthen placed inside the manually created pocket to fill the space of theexcised corneal tissue. The transplanted disk of tissue initially staysin place by the pumping mechanism of the corneal endothelial cells andthen gradually heals into place permanently. One significant advantageof this technique is that post-operatively, the eye is much lesssusceptible to injury than in other methods of corneal transplantation.Moreover, because the transplantation occurs within a pocket of thecorneal tissues, the transplant is well protected by the intactboundaries of the corneal pocket. Unfortunately, a disadvantage of suchfree hand technique is that it is very difficult to manually create apocket in the corneal tissues, wherein the pocket is of uniform depth.Rather, it is quite possible to either prematurely cut through thedeepest layers of the cornea and thus enter the anterior chamber, or toaccidentally cut too superficially and thus exit from the superficialcornea. The inability to create a uniform pocket will necessitate theabandonment of posterior lamellar keratoplasty and may requireconversion to traditional penetrating keratoplasty.

[0020] Using a motorized microkeratome for posterior lamellarkeratoplasty involves the creation of a flap of corneal tissue with amotorized blade. This is followed by excision of a disk of the deepestlayers of the cornea including the endothelium. The excised disk ofcorneal tissue (including the endothelium) is replaced by the samelayers from a donor cornea. The donated corneal disk is then secured inplace with sutures. The corneal flap of the recipient cornea is alsosecured with sutures for up to several months. A disadvantage of thistechnique is that, like penetrating keratoplasty, the inside of the eyeis exposed to atmospheric pressure and therefore there is also a risk ofsuprachoroidal hemorrhage with this technique. Another disadvantage isthat post-operatively the eye is still fairly vulnerable to injury. Forexample, even minor trauma could result in flap dislocation or ruptureof the transplant-recipient junction.

[0021] Recently anterior lamellar keratoplasty and posterior lamellarkeratoplasty have also been performed on an experimental basis where theincisions have been created with a laser. Two disadvantages of thistechnique are the high cost of lasers and potential difficulty for thelaser to create incisions in corneas that are scarred or opacified. SeeU.S. Pat. No. 6,325,792 to Swinger et al.

[0022] Ametropia, the incorrect focusing of light rays onto the retina,is the most common cause of decreased vision in humans. Common examplesof ametropia include myopia, hyperopia or hypermetropia, andastigmatism. Because the cornea is the primary focusing lens in the eye,modification of the shape of the cornea by surgery has the ability tocause dramatic improvements in vision in patients that have ametropia.

[0023] LASIK (laser assisted in situ keratomileusis) is a method oflaser vision correction that can dramatically improve vision by changingthe shape of the cornea to allow the proper focus of light rays onto theretina. In the LASIK technique, a motorized blade is used to cut away athin flap of tissue from the front of the cornea. The flap of cornealtissue is then lifted to expose the interior surface of the cornea. Thisexposed interior surface is then reshaped by the application of laserlight. The flap of corneal tissue is then repositioned over the reshapedinterior portion of the cornea. The flap initially stays in positionthrough the natural pumping mechanism of the corneal endothelial cellsand then gradually heals into place permanently. In this procedure,there is considerable variability in the size and shape of the lasertreatment. However, with current corneal surgical devices the size andshape of the flap that covers the laser treatment is unfortunatelyrather limited. Another disadvantage of this procedure is that somecorneal tissue is destroyed permanently as part of the vision correctionprocess, due to the vaporization of corneal tissue by the laser.

[0024] Another vision improvement technique is keratophakia.Keratophakia is the insertion of a lens within the cornea. Keratophakiacan also modify the curvature of the cornea for the purpose of improvinga patient's vision. In Keratophakia, a pocket is made within the cornealtissues usually by means of a hand held blade. U.S. patent applicationSer. No. 2001/0004702 to Peyman describes a non-motorized apparatus forcreating such a pocket within the cornea. In the Peyman device, movementof the blade is created by manually twisting the blade. After the pocketis made within the corneal tissue, an organic or synthetic lens isimplanted within the pocket to reshape the cornea in order to change thefocus of light rays. The disadvantage of either a manual technique or anon-motorized technique is that the uniformity of the pocket is largelydependent on the surgeon's skill and experience and therefore there canbe a high degree of variability. The Peyman device is designed only forthe purpose of creating a pocket within the cornea of a living patientand cannot be used for the purpose of creating a pocket within a donorcornea.

[0025] U.S. Pat. No. 6,599,305 to Feingold describes a motorizedapparatus for creating a pocket within the cornea for the purpose oflens implantation. In this invention, the blade assembly oscillateslaterally while extending forward into the cornea to form the pocket,and the amplitude of the lateral oscillation increases as the blade goesbeyond an entry incision into the cornea. A disadvantage of this methodof automatically creating a pocket within the cornea is that the widthof the entry incision will necessarily be relatively large compared tothe width of the pocket. The Feingold device cannot create a pocket withan entry incision width that is less than half of the maximum width ofthe pocket. The Feingold device also cannot create a pocket that is morethan twice the width of the cutting blade. Having a larger entryincision will cause slower healing, increase the risk of induced cornealastigmatism, and usually necessitate the need for suture closure. TheFeingold device is designed exclusively for the purpose of creating apocket within the cornea of a living patient and cannot be used for thepurpose of creating a pocket within a donor cornea.

[0026] Because of the apparent difficulties with the current cornealsurgical devices there is still a continuing need for an improvedapparatus and method to create a pocket, flap, or a cap of cornealtissue in a live or donor cornea, wherein the pocket, flap, or cap is ofuniform depth and thickness. In particular, it would be desirable toprovide methods and systems for cutting cornea pockets where the ratioof pocket width to width of the entrance channel is maximized.

[0027] Description Of The Background Art.

[0028] U.S. Pat. Nos. 6,599,305 B1 and 5,964,776, describe methods andapparatus for creating corneal pockets for implanting lenses. Otherpertinent patents and published applications include 6,385,260;6,344,046; 6,332,890; 6,325,792; 6,296,650; 6,277,134; 6,228,099;6,139,560; 6,045,563; 6,045,562; 6,022,365; 5,944,731; 5,807,380;5,779,723; and US2002/0,091,401; US2002/0045910; and US2001/0004702.

BRIEF SUMMARY OF THE INVENTION

[0029] Improved systems and methods for cutting the cornea of an eye,particularly for forming internal pockets in the eye, are provided. Thesystems and methods allow for corneal pocket formation using arelatively small initial incision while providing a pocket having arelatively large width or diameter.

[0030] Systems for cutting the cornea of an eye in accordance with thepresent invention comprise a frame, a moveable member having a cuttingblade at a distal end thereof, and a driver coupled to the moveablemember. The frame can be immobilized relative to the eye and willusually comprise a suction ring and an applanating plate. The driver isadapted to both translate and rotate the moveable member relative to theframe. By having such freedom of movement, motion of the moveable membercan be limited within a relatively small entrance incision while motionof the cutting blade is relatively unrestricted.

[0031] In the exemplary embodiments, the moveable member is linear, butthe moveable member could also be non-linear, for example being curved,curved-in-part, angulated, or having other non-linear configurations.

[0032] The moveable member may be suspended relative to the frame in avariety of ways. Most commonly, the moveable member will be positionedto rotate on a pivot, where the pivot can be translated and/or movedover a two-dimensional plane. Alternatively, the moveable member may bemounted a fixed pivot, where the moveable member can translate and/orrotate over the pivot. When the pivot translates, the path oftranslation may be linear or non-linear, typically being linear andaligned with a centerline through the frame. The pivot itself maycomprise a pin or other protrusion to support the moveable member. Inother embodiments, however, the “pivot” may comprise lateral restraintswhich allow the moveable member to translate while limiting lateralmovement of the moveable arm at the point of the restraints, i.e.,mimicking a pivotal support where the arm translates and rotates overthe pivot.

[0033] In other embodiments, the moveable member will be manipulated ona “pivotless” system. Such pivotless systems may provide for essentiallyunlimited freedom of motion in a two-dimensional plane. Such drivers maycomprise parallelogram linkages, cable supports, and other knownmechanical drive systems.

[0034] In all cases, the moveable arm may be manually positioned, oftenusing a template or other motion guide. In the presently preferredembodiments, however, the moveable arm will be driven by a poweredsystem, typically a motor, which is automatically controlled using acomputer, programmable controller, or other control system which can beprogrammed to achieve a precise and selectable pocket size.

[0035] The systems of the present invention will be particularly usefulfor performing corneal transplants. In such cases, the systems willfrequently further comprise an anterior chamber maintainer which can beused to hold a donor cornea prior to harvesting the corneal implant. Inparticular, the anterior chamber maintainer will be adapted for usetogether with the moveable member, cutting blade, and driver in place ofthe corneal frame. In that way, the implant which is cut from the donorcornea will precisely match the thickness of the hole which is cut bythe same system when used on the cornea with the frame. The peripheraldimensions of the implant will, of course, be determined by the separatecutting blade which is used for both the donor cornea and the recipientcornea.

[0036] The present invention further provides methods for forming apocket in a cornea. The methods comprise advancing a cutting element ata distal end of a moveable member through an entry incision in thecornea. Movement of the movable member is controlled to cause thecutting element to create a pocket having a width in at least onedirection through a center of the cornea which is greater than twice awidth of the entry incision. Usually, the entry incision has a widthwhich is no greater than 4 mm and the pocket has a width which isgreater than 8 mm. Preferably, the pocket will have a width of at least8 mm, and in some cases the width will be at least 10 mm.

[0037] The ratio of the pocket width or diameter relative to the entryincision width can be maximized by using a moveable member having arelatively narrow width, at least at a region through which the memberpasses through the entry incision. Usually, the width will be no greaterthan 1 mm over this region.

[0038] Controlling the moveable member typically comprises bothtranslating and rotating the moveable member relative to the cornea.Such translating and rotating can be achieved in a number of ways,generally as described above in connection with the systems of thepresent invention. Briefly, the moveable member may be rotated on apivot point, where the pivot point is capable of being translated and/orthe moveable member may translate over the pivot point. In otherembodiments, the pivot point may be fixed relative to the cornea and themoveable member translated over or under the pivot point. In addition tobeing useful for performing corneal transplantation, the methods of thepresent invention can be used for implanting a lens in the pocket whichis formed. Frequently, the lens will restrained to pass through thenarrow width entry incision and released to its expanded configurationwithin the pocket. The methods, of course, are also useful forimplanting a corneal graft in the pocket as generally described above.

[0039] In yet another aspect of the present invention, a method forcutting a pocket in a cornea comprises advancing a cutting element atthe distal end of a moveable member through an entry incision into thecornea. Movement of the moveable member is controlled to cause thecutting element to create a pocket, where the moveable member is bothrotated and translated relative to the cornea. The rotation andtranslation of the moveable member may be achieved by any of thetechniques described above using a pivot point or using a pivotlessdriver. Preferred dimensions of the entry incision and ratios betweenthe width of the entry incision and dimensions of the corneal pockethave also been described previously.

[0040] In a still further aspect of the present invention, methods fortransplanting a cornea comprise creating a pocket in the cornea of thepatient, where the pocket has an entry incision with a width less thanthat of the pocket. A cylinder of tissue is removed from over or underthe pocket while the remaining portions of the corneal tissue remainintact to limit exposure of the interior of the eye to atmosphericpressure. The removed cylinder of tissue may then be replaced with donortissue, where the interior of the cornea remains protected from exposureto the atmospheric pressure. The procedure is useful for both anteriorlamellar keratoplasty and posterior lamellar keratoplasty. The pocket istypically created by advancing a blade into the cornea while flatteningthe cornea with an applanator. Optionally, the donor tissue may beharvested with the same pocket making device that was used to create thepocket in the recipient cornea. In such instances, the donor cornea maybe supported on an anterior chamber maintainer which the cornea is cutwith the cutting element.

[0041] In an additional aspect of the system of the present invention,an anterior chamber maintainer for harvesting a donor cornea comprises asupport for the donor cornea useful while a pocket forming devicecreates a pocket within the donor cornea.

[0042] The inventions described above provide a number of advantages andbenefits. In preferred aspects, the present invention provides a systemfor cutting the cornea of an eye, comprising a moveable member that maybe translated or rotated within a plane in a non-manual or manualfashion, a cutting element at one end of the moveable member, a suctionring for stabilizing the cornea, and an applanator for flattening thecornea.

[0043] In preferred aspects, the moveable member has a cutting blade atone end, a pivot element disposed thereon, a cutting guide restraintdisposed thereon, a mechanism for oscillating the moveable member aroundthe pivot element, a cutting guide software program which controls aprogrammable motor that engages the cutting guide restraint on themoveable member and thereby limits the degree of angular movement of thecutting blade as the moveable member rotates about the pivot element,and a cutting guide software controlled positioning system configured toadvance the moveable member with respect to the cornea

[0044] In further preferred aspects of the invention, the moveablemember, cutting element, suction ring, and applanator are alldisposable.

[0045] In still further preferred aspects, the cutting element may be asolid blade or any other cutting mechanism appropriate to cut the corneae.g. electromagnetic energy such as a laser or plasma field.

[0046] In alternate preferred aspects of the invention, the pivotelement of the moveable member may be adjustably or selectivelypositioned relative to the cutting path. Adjusting the position of thepivot element allows the cutting blade to move within a pocket that hasa small opening.

[0047] In one embodiment, the position of the pivot element isdetermined by a cutting guide software program that commands aprogrammable motor to move the pivot element along a specified path. Thepath of the pivot element of the moveable member may be either linear ornon-linear.

[0048] Other embodiments can be envisioned where the movement of thepivot element is controlled by wires, pistons, pneumatics, or magnetism,these are all within the scope of the present invention. In additionalpreferred aspects, the angles of the cutting guide restraint and thecutting blade are determined by the relative position of the pivotelement of the moveable member and a restraining element engaged to thecutting restraint.

[0049] In preferred aspects the cutting blade is able to create a pocketwith an internal maximum width that is larger than twice the entryincision width.

[0050] In further preferred aspects of the invention, the moveablemember may have a fixed pivot point relative to the cornea. The moveablemember may translate over or under the pivot point as well as rotatearound the pivot point while a cutting element attached to one end ofthe moveable member creates a cut in the cornea.

[0051] In alternative preferred aspects, the moveable member may have afixed pivot point relative to the cornea and the moveable member is ableto shorten and lengthen its portion that is proximal to the cornea whilea cutting element attached to one end of the moveable member creates acut in the cornea.

[0052] In other alternate preferred aspects of the invention, themoveable member may have no pivot element. The angular position of themoveable may be determined by applying a pushing or pulling force to atleast one point on each side of the moveable member. Angular andtranslational positioning of the moveable member may be achieved by anyform of a mechanical, electrical, magnetic or pneumatic system, but thepresent invention is not so limited.

[0053] In yet other preferred aspects, the cutting element may bedeformable in shape and size. This advantageously allows a larger pocketto be created through a relatively small opening.

[0054] In still more preferred aspects of the invention, one or all ofthe following components are disposable: the cutting guide, themechanism for oscillating the moveable member, the applantor, and thesuction ring.

[0055] In yet more preferred aspects, the cutting guide softwaredetermines the shape of a cut made by the cutting blade bysimultaneously controlling the angle of the cutting blade and therelative position of the cutting blade to the cornea. The cutting guidesoftware program controls the angle and position of the blade by givingcommands to one or more programmable motors such as a stepper or servomotor to change the angle of the blade as the blade is advanced into thecornea by a programmable drive motor.

[0056] In additional alternate preferred aspects, the mechanism foroscillating the moveable member around the pivot element may compriseany form of a mechanical, electrical, magnetic or pneumatic system, butthe present invention is not so limited.

[0057] In yet additional alternate preferred aspects, the positioningsystem that moves the moveable member relative to the cutting guide maycomprise any form of a mechanical, electrical, magnetic or pneumaticsystem, but the present invention is not so limited.

[0058] In specific aspects of the invention, the present invention alsoprovides a method of cutting a cornea, including: penetrating a corneawith a cutting element at one end of a moveable member; non-manuallymoving or rotating a moveable within a plane; and advancing the moveablemember with respect to the cornea, thereby cutting the cornea with thecutting blade.

[0059] In preferred aspects, a pivot point of the moveable member isadvanced with respect to the cornea in order to advance the blade intothe cornea. In one embodiment, the position of the pivot point may beadjusted in a controlled fashion by a linkage to a programmable motor.In another embodiment, no pivot element is used and the angle andposition of the moveable member is not limited by a pivot point. Infurther preferred aspects, the cornea is stabilized with a suction ring;and the front surface of the cornea is flattened with an applanatorprior to penetrating the cornea with the cutting blade. In alternatepreferred aspects, a donor cornea is stabilized prior to cutting by anoptional anterior chamber maintainer that attaches to the presentinvention.

[0060] In preferred aspects, the path of the moveable member may eitherbe linear or non-linear as it cuts the cornea. An example of anon-linear path would be an arcuate path. In one embodiment of thedevice, the moveable member is rotated into the cornea as it oscillatesto create the pocket.

[0061] In different embodiments, the applanator may be held at a fixedposition as the cutting blade cuts through the cornea, or the applanatormay be advanced across the cornea as the cutting blade cuts through thecornea. The applanator may be in the form of a plate that can flattenthe majority of the cornea or it may be an applanator that is onlysufficiently large to flatten the portion of the cornea that is beingcut. The applanator may also move in conjunction with the cutting blade,so that the portion of the cornea that is to be cut will be flattened inadvance of the cutting blade.

[0062] Accordingly, the present invention provides a system and methodof creating a pocket of uniform depth in the cornea. The pocket can bemade of various shapes and sizes, between various layers of a live ordonor cornea.

[0063] One advantage of the present system is that it is able to createa pocket of uniform depth within the cornea. Another advantage of thepresent system is that it is able to create a cut into the corneawherein the cut has an external opening that is smaller than theinternal dimensions of the pocket. In particular, the present system isable to automatically or manually create a pocket with an externalincision width that is smaller than half of the maximum pocket width,e.g., larger than twice the width of the cutting blade.

[0064] Accordingly, the present invention may be used to transplant aportion of the inner layer of the cornea with a number of advantages. Asignificant safety advantage is that the transplantation may occur in arelatively closed system protected from atmospheric pressure. Thisreduces the risk of expulsive suprachoroidal hemorrhage. Being able tocreate a relatively large pocket also has the advantage of being able totransplant a larger section of the donor cornea with a correspondinglarger number of healthy corneal endothelial cells. Additionally, havingthe external opening smaller than the internal dimensions of the pocketwill also make the eye much more resistant to trauma than would be thecase in penetrating keratoplasty. Moreover, the ability to make a smallexternal opening will increase the speed of healing, decrease surgicallyinduced astigmatism, and allows sealing of the wound without the use ofsutures.

[0065] The present invention also allows the convenient harvesting of adonor graft for both anterior and posterior lamellar keratoplasty. Theoptional anterior chamber maintainer device allows the creation of apocket within a donor cornea. A disk of donor tissue from above or belowthe pocket can then be excised with scissors or a trephine for thepurpose of anterior or posterior lamellar keratoplasty. Advantageously,the same pocket making device that is used to create a pocket within thelayers of the recipient cornea may be used to harvest the donor cornealtissue, thus increasing the ease of the procedure and eliminating theexpense of purchasing a separate device to harvest the donor cornealtissue.

[0066] The present invention also describes an anterior chambermaintainer that may be adapted to function with any pocket formingdevice such as those described by Peyman in U.S. patent application Ser.No. 20010004702 and Feingold in U.S. Pat. No. 6,599,305 to allowharvesting of donor corneal tissue .

[0067] The present invention may also be used to insert a reversiblydeformable lens into the cornea. Having an external opening that issmaller than the internal dimensions of the pocket will help protectagainst extrusion of the lens. Having a larger pocket area also has theadvantage of being able to insert a larger lens, which can result inimproved vision especially for patients that have large pupils.Specifically, a pocket which has a width that is larger than at least 5mm will be able to contain a lens that is at least 5 mm in diameter. Alens inserted within the cornea with a diameter of at least 5 mm is morelikely to be compatible with acceptable vision than a lens smaller than5 mm. Moreover, the ability to make a small external opening willincrease the speed of healing, decrease surgically induced astigmatism,and allows sealing of the wound without the use of sutures.

[0068] The reversibly deformable lens may be folded or squeezed byforceps to allow entry through the small external opening. Thedeformable lens may also be composed of a thermally reactive polymerthat allows the implant to be in a shape that easily fits through thesmall external opening at room temperature (e.g. a rod) and then allowsthe implant to change into a final shape (e.g. a disk) that is wellretained within the pocket. In preferred aspects the deformableintracorneal lens should be bio-compatible with the cornea and willallow diffusion of oxygen, carbon dioxide, other gases, glucose andother nutrients through the implanted lens and cornea.

BRIEF DESCRIPTION OF THE DRAWINGS

[0069]FIG. 1 is a top plan view of the moveable member and associatedcutting guide.

[0070]FIG. 2 is a side elevation view corresponding to FIG. 1.

[0071]FIG. 3 is a view similar to FIG. 1, but additionally showing (indotted lines) the moveable member moved to a second position at which acutting guide restraint on the moveable member contacts a side of thecutting guide.

[0072]FIG. 4 is a side elevation view corresponding to FIG. 3.

[0073]FIG. 5A is a top plan view showing the moveable member moved froma first position at which the cutting guide restraint contacts one sideof the cutting guide (shown in solid lines) to a second position atwhich the cutting guide restraint contacts the other side of the cuttingguide (showing in dotted lines).

[0074]FIG. 5B is a top plan view showing the linkage of the moveablemember to a motor as consisting of two links connected by a joint.

[0075]FIG. 5C is a schematic side elevation view showing that thepresence of two sequential links connected by a joint can minimizevertical up and down motion of the moveable member.

[0076]FIG. 6A is a schematic side elevation view of an embodiment of theinvention in which a non-moving applanating plate flattens the surfaceof the cornea prior to cutting.

[0077]FIG. 6B is a schematic side elevation view of an embodiment of theinvention in which a non-moving applanating plate flattens the surfaceof the cornea during cutting.

[0078]FIGS. 7A and 7B are sequential schematic side elevation views ofan embodiment of the invention in which an applanating plate advancesacross the surface of the cornea simultaneously with the cutting bladecutting through the cornea.

[0079]FIG. 7C is a front elevation view of the embodiment of theinvention shown in FIGS. 7A and 7B.

[0080]FIG. 8A is a side elevation view of an optional anterior chambermaintainer that may be affixed to the suction ring of the presentinvention.

[0081]FIG. 8B is a sectional side elevation view corresponding to FIG.8A, showing inner workings of the anterior chamber maintainer.

[0082]FIG. 9 is a sectional side elevation view of an embodiment of theinvention in which an operator manually depresses a plunger to advancethe cutting blade.

[0083]FIG. 10 is a top plan view of an embodiment of the invention inwhich the cutting blade is advanced through a curved path into thecornea.

[0084]FIG. 11 is corresponding side and top views of anterior lamellarkeratoplasty procedure performed with prior art techniques.

[0085]FIG. 12 is corresponding side and top views of anterior lamellarkeratoplasty procedure performed with a technique in accordance with thepresent invention.

[0086]FIG. 13 is corresponding side and top views of a posteriorkeratoplasty procedure performed with prior art techniques.

[0087]FIG. 14 is corresponding side and top views of a posteriorkeratoplasty procedure performed with a technique in accordance with thepresent invention.

[0088]FIG. 15A is a top plan view of a mechanical system for moving amoveable member and cutting blade in accordance with the principles ofthe present invention.

[0089]FIG. 15B is a side view of a system employing the mechanism ofFIG. 15A.

[0090]FIG. 16 illustrates an alternative mechanical system formanipulating a moveable member and cutting blade.

[0091]FIG. 17 illustrates a system where the moveable member is mountedon a pivot point which moves over a circular path.

[0092]FIGS. 18A-18D provide an example of the motion of the cuttingsystem of FIG. 17.

[0093]FIG. 19 is yet another embodiment of a mechanism for manipulatinga moveable member and cutting blade in accordance with the principles ofthe present invention.

[0094]FIGS. 20A-20D illustrate how a large pocket can be made through asmall incision over a fixed pivot point.

[0095]FIG. 21 illustrates a pivotless driver for manipulating a moveablemember and cutting blade in accordance with the principles of thepresent invention.

[0096]FIGS. 22A-22D illustrate a prior art cutting system which lacksthe advantages of the present invention.

[0097]FIGS. 23A and 23B illustrate a system constructed in accordancewith the principles of the present invention having an applanatorslightly larger than the cutting element.

[0098]FIGS. 23C-23F illustrate movement of the cutting blade in thesystems of FIGS. 23A and 23B as illustrated.

[0099]FIGS. 24A-24C illustrate methods in accordance with the principlesof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0100] In preferred aspects, the present invention provides a cornealsurgery system that can be used to cut a live or donor cornea to form apocket, flap or cap by separating the layers of the cornea.Specifically, the present invention provides a system for automaticallycreating a pocket of uniform depth, which can be of various shapes andsizes, between the layers of a live or donor cornea. The presentinvention may also be used to create a flap or cap of corneal tissue ina live or donor cornea.

[0101] In accordance with the present invention, a system for cutting acornea is provided. The system comprises a cutting blade that is movedback and forth in an arcuate path while simultaneously being advanced tocut through a cornea. As will be explained, the degree of angularmovement of the cutting blade is limited by contacts between a moveablemember (to which the cutting blade is attached) and a cutting guide.

[0102] Operation of the present invention can be understood by referenceto FIGS. 1 to 5 which illustrate the movement of the moveable memberwith respect to the cutting guide.

[0103]FIGS. 6A to 7C and 9 and 10 show further details of variousembodiments of the present invention.

[0104]FIGS. 8A and 8B show an optional attachment device that can beused with various embodiments of the present invention.

[0105] Lastly, FIGS. 11 and 13 show surgical cutting proceduresperformed by pre-existing techniques. FIGS. 12 and 14 show comparablesurgical cutting procedures performed with the system of the presentinvention.

[0106] Referring first to FIGS. 1 and 2, a moveable member 10 isprovided. Moveable member 10 has a cutting blade 12 at one end. Inoptional aspects, cutting blade 12 may be made of steel, stainlesssteel, sapphire, diamond, plastic or ceramic, but is not so limited.Rather, any material suitable for cutting the cornea may be used.Moveable member 10 has a pivot 14 thereon. As will be shown, moveablemember 10 is oscillated such that it sweeps back and forth in an angularpath of direction O about its pivot 14. Moveable member 10 furtherincludes a cutting guide restraint 16 projecting therefrom. Cuttingguide restraint 16 is received with a hole 22 of a cutting guide 20.

[0107] As shown in FIGS. 2 and 4, cutting guide restraint 16 projectsfrom the bottom of moveable member 10 and cutting guide 20 is positionedbelow moveable member 10. The present invention is not so limited.Alternate embodiments are possible, all keeping within the scope of thepresent invention. For example, cutting guide restraint 16 may insteadproject from the top of the moveable member with cutting guide 20 beingplaced above moveable member 10. Other designs are also possible.

[0108] In accordance with the present invention, corneal cutting isperformed by angular back and forth movement (i.e.: oscillation indirection O) of moveable member 10 about pivot 14 at the same time thatpivot 14 is advanced in direction D with respect to cutting guide 20. Asmoveable member 10 is advanced in direction D, cutting guide restraint16 will contact successive locations around the sides of hole 22 incutting guide 20. The novel shape of hole 22 in cutting guide 20 willhave the effect of limiting the degree of angular (i.e., side to side)motion of cutting blade 12. Accordingly, as cutting blade 12 is advancedin direction D with respect to cutting guide 20 (by advancing pivot 14of moveable member 10 in direction D), the novel shape of hole 20 willcause cutting blade 12 to cut a preferred shape of cut in the cornea.

[0109] This can be seen as follows. Referring to FIG. 3, moveable member10 is rotated in direction R about pivot 14 to the position shown indotted lines as 10A. At such location, cutting guide restraint reachesthe position shown in dotted lines as 16A (at which time it contacts theside of hole 22, as shown). Blade 12 is thus not able to rotate furtherin direction R than to the position shown in dotted lines as 12A.Thereafter, moveable member 10 will be rotated in the opposite directionsuch that cutting guide restraint 16 will instead contact the oppositeside of hole 22 (thus limiting maximum angular movement in the oppositedirection).

[0110] Concurrently, moveable member 10 will be moved in direction Dwith respect to cutting guide 20. This movement is shown by referringfirst to FIG. 4 and then to FIG. 2. (FIG. 4 shows the position of themoveable member with respect to the cutting guide when cutting is firstcommenced, and FIG. 2 shows the position of the moveable member withrespect to the cutting guide after cutting has been carried out for sometime.)

[0111]FIG. 5A illustrates a mechanical system for oscillating moveablemember 10 back and forth in direction O. Specifically, FIG. 5A showsmoveable member 10 at a first maximum angular extension (shown in solidlines) and moveable member 10 at an opposite maximum angular extension(shown in dotted lines). In preferred aspects of the invention, moveablemember 10 includes a flexible portion 18. Flexible portion 18 mayoptionally comprise a spring or a flexible piece of plastic or rubber.As can be seen, an advantage of having portion 18 flexible is that itbends when cutting guide restraint 16 is stopped from further angularmovement by its contact with the sides of hole 22. A system 30 foroscillating moveable member 10 may include a motorized mechanicallinkage for rotating moveable member 10 back and forth by alternatinglymoving flexible portion 18 back and forth in a direction generallyperpendicular to direction D. For example, system 30 may include a motor32 that rotates a wheel 34 (by rotating shaft 35). A pin 33 iseccentrically mounted to wheel 34 such that as wheel 34 rotates, themovement of pin 33 causes link 36 to move back and forth, therebyrepetitively moving moveable member 10 back and forth between positions(shown as 10 and 10A).

[0112] In preferred aspects, link 36 may include more than one linkmember connected together in series. An advantage of having link 36include more than one link member is that this can minimize up and downmovement of the flexible portion 18 and moveable member 10 as pin 33moves around shaft 35. FIG. 5B shows link 36 consisting of portions 36A,36B, and 36C. Portion 36C is a joint which connects portion 36A and 36B.FIG. 5C shows how joint 36C allows portion 36A to move in a vertical upand down motion while portion 36B moves predominantly in a transversehorizontal motion relative to pivot 14. Portion 36B, therefore transmitspredominantly horizontal back and forth motion to flexible portion 18and moveable member 10 around pivot 14 and minimizes up and down motion.

[0113] As can be seen in FIGS. 1, 3 and 5, hole 22 in cutting guide hasa novel shape. In particular, hole 22 has a “gourd” or a “bowling pin”shape. The present inventor has determined that such “gourd” or a“bowling pin” shaped hole will result in a corneal cut that is roughlyshaped like an “ice cream cone” (i.e. a triangular section with aconvexly-curved end). Preferably, hole 22 will have a symmetrical shape.As will be shown, a particular advantage of this shape of cut is that itwill create a pocket in the cornea wherein the opening through thesurface of the cornea is smaller in width than the internal dimensionsof the pocket.

[0114] In accordance with the present invention, an applanating plate ispositioned against the front surface the cornea and the intraocularpressure is elevated by a suction ring during the time the cornea is cutby the movement of the cutting blade. The applanating plate presses downagainst the front surface of the cornea and the intraocular pressurepresses up against the back surface of the cornea, thereby uniformlyflattening a portion of the cornea. This has the advantage of ensuring auniform thickness of the cornea is cut by the cutting blade when forminga pocket, flap, or cap.

[0115] In one embodiment, the applanating plate is positioned at a fixedlocation on the surface of the cornea prior to commencing cutting of thecornea with the cutting blade. An example of such system is shown inFIGS. 6A and 6B. In an alternate embodiment of the invention, theapplanating plate is advanced over the surface of the corneaconcurrently with the cutting blade penetrating and cutting across thecornea. An example of such system is shown in FIGS. 7A to 7C.Additionally, FIGS. 7A to 7C show an optional anterior chambermaintainer 60 which is especially useful when cutting a donor cornea. Itis to be understood that anterior chamber maintainer 60 is an optionalattachment that may or may not be used with the various embodiments ofthe invention shown in FIGS. 6A to 7C, as desired.

[0116] Referring first to FIG. 6A, when vacuum pump 59 connected tosuction ring 50 by tubing 57 via tubing connector 55, creates a vacuumto a predetermined level, suction ring 50 holds cornea C (positionedtherearound) in a fixed position. The vacuum transmitted by suction ring50 also raises the pressure against the rearward surface of cornea Cbecause the vacuum causes the eyeball to partially squeeze into thesuction ring. The applanating plate 52 pushes down against the frontsurface of the cornea, thereby flattening the cornea. As illustrated, amember 42 is used to advance pivot 14 in direction D from the positionshown in FIG. 6A to the position shown in FIG. 6B. (The relativemovement of cutting guide restraint 16 within cutting guide 20 can beseen.) In accordance with the present invention, member 42 may includeany form of mechanical linkage, guide rails or even simply a portion ofthe housing of the device.

[0117]FIGS. 7A to 7C show an alternate embodiment of the invention inwhich applanating plate 52 is moved across cornea C concurrently withblade 12 advancing (i.e. cutting through the cornea) in direction D.Moveable member 10, cutting guide 20 and system 30 are all positionedinside housing 40. As was explained above, system 30 causes moveablemember 10 to rotate back and forth around pivot 14, with cutting guiderestraint 16 is received within cutting guide 20. (In contrast to theembodiment of FIGS. 6A and 6B; however, pivot 14 instead projects fromthe bottom of moveable member 10, and cutting guide 20 is positionedabove moveable member 10.) Member 42 is advanced in direction D withinhousing 40, thereby moving moveable member 10 in direction D. Cuttingguide 20 is connected to housing 40 such that cutting guide restraint 16moves along through hole 22 therein. Further details can be seen in FIG.7C in which supports 45 hold applanating plate 52 within housing 40 suchthat moveable member 10 is free to move side-to-side therebetween.

[0118]FIGS. 7A and 7B show an optional anterior chamber maintainer 60that may be used as an attachment to the present invention. Furtherdetails of the anterior chamber maintainer 60 are shown in FIGS. 8A and8B. Anterior chamber maintainer 60 is specifically used when cuttingtissue in a donor cornea. The donor corneal tissue is usually providedto the surgeon in the form of an excised cornea with a small rim ofsurrounding scleral tissue. As stated above, the present invention isdesigned to cut the cornea of a living complete eyeball. However, it isalso necessary to have an attachment that will also enable the inventionto cut a donated cornea that has been excised from the donor eyeball.

[0119] In accordance with the present invention, an optional anteriorchamber maintainer 60 is provided to hold a donor cornea stable afterthe donor cornea has been cut away from the donor eyeball. As shown inthe exploded view of FIGS. 8A and 8B, a cut away donor cornea C isplaced on top of anterior chamber maintainer 60. In this preferredembodiment, suction ring 50 has an inner threading 63. The body of theanterior chamber maintainer 61 has an outer threading 62. The outerthreading 62 is received into the inner threading 63 of suction ring 50.The inner threading 63 of suction ring 50 connects to outer threading ofbody 61, thereby firmly holding cornea C in place by trapping cornea Cbetween suction ring 50 and body 61. The front surface of the corneaprotrudes through the opening 51 of the suction ring. The body 61 has aninterior chamber 66 that is filled with fluid or gas. A bottom portion68 screws into the bottom end of interior chamber 66. By rotating bottomportion 68, the volume of interior chamber 66 can be adjusted. The topend 69 of fluid chamber 66 is open such that the fluid or gas withininterior chamber 66 provides pressure against the rear surface of thedonor cornea C. By providing pressure against the rear surface of donorcornea C, anterior chamber maintainer 60 simulates the pressures thatwould exist behind cornea C in a living eyeball. Moreover, the pressuresproduced in interior chamber 66 applied to the rear surface of cornea Callows the donor corneal tissue to be pressed flat against applanatingplate 52 so that a cut of uniform depth can be made by blade 12. Theamount of pressure inside the interior chamber may be measured by apressure gauge or sensor connected to opening 67.

[0120]FIGS. 8A and 8B illustrate the tubing connector 55 on the topsurface of the suction ring 50. This is an alternate location for tubingconnector 55. In FIGS. 6A, 6B, 7A, 7B, and 9 the tubing connector 55 isshown on the side surface of the suction ring 50. FIG. 8B illustratesthat there is a hollow space 56 inside tubing connector 55 whichcommunicates with the inside of suction ring 50 that allows the vacuumpump 59 to generate vacuum inside suction ring 50. Advantageously, thegeneration of vacuum by vacuum pump 59 is not necessary for a cut to bemade in the donor cornea C, because the cornea is already fixed inposition by the anterior chamber maintainer 60 and the pressure on therear surface of the cornea can also be sufficiently elevated by theanterior chamber maintainer 60.

[0121]FIG. 9 shows another embodiment of the present invention in whichthe cutting blade is manually advanced by an operator. Within housing 70are provided a guide rail or track 72 along which a cutting mechanism 74moves. Cutting mechanism 74 may be a self-contained unit that includesmoveable member 10, cutting guide restraint 16, a system for oscillatingmoveable member 10 about a pivot 14 thereon. A plunger 78 is connectedto cutting mechanism 74. A spring 76 is connected at one end to housing70 and at the other end to cutting mechanism 74. Spring 76 is a tensionspring that tends to move cutting mechanism 74 so that blade 12 isretracted (as shown). When the operator depresses plunger 78, spring 76will lengthen, and cutting mechanism 74 will move forward along track 72such that blade 12 on moveable member 10 will advance betweenapplanating plate 52 and suction ring 50, cutting through the cornea C.The interaction of cutting guide restraint 16 and cutting guide 20 willcause the cut to be of a preferred shape as was described above. Spring76 will provide resistance to the forward motion of cutting mechanism 74along track 72, thus , limiting uncontrolled forward motion of moveablemember 10's cutting blade 12. Optionally, a liquid dispensing system 71to spray fluid to cool the cutting blade and the cornea during cutting.Such a liquid dispensing system may be incorporated into any of thevarious other embodiments of the invention, as desired.

[0122]FIG. 10 illustrates yet another embodiment of the invention inwhich a blade holder 80 having a blade 82 at one end is connected tomoveable member 83 which pivots about a pivot point 84. As shown herein,blade 82 may be wider than the bladeholder 80, if desired. (Similarly,blade 12 may be wider than moveable member 10 in FIG. 1, if desired.) Amotor 90 moves a linkage 88 back and forth. Linkage 88 is connected tomoveable member 83 by flexible member 86 such that moveable member 83 ismade to oscillate back and forth about pivot point 84. Thus, bladeholder 80 and blade 82 oscillates back and forth in direction O. Bladeholder 80 has a cutting guide restraint 87 disposed thereon. Cuttingguide restraint 87 mates with a cutting guide (not shown) the shape ofwhich limits maximum angular movement of blade 82, in the mannerpreviously described above. The various components of the invention aremounted to a plate 92 that is connected to a rotatable member 94 that isrotated in direction R such that plate 92 is moved in direction R suchthat blade 82 and blade holder 80 will advance between applanating plate52 (thereabove) and suction ring 50 (therebelow) to cut the flattenedcornea.

[0123] As illustrated in various figures herein, pivot 14 and cuttingguide restraint 16 may each comprise protrusions extending from moveablemember 10. Moreover, in various figures herein, cutting guide 20 isillustrated as comprising a hole 22. The present invention is not solimited. For example, the pivot 14 on moveable member 10 may insteadcomprise a hole dimensioned to receive a protrusion therein. Moreover,the cutting guide restraint may instead comprise a slot with the cuttingguide comprising some form of protrusion interacting therewith.

[0124] As stated above, the present invention may be used to for cuttinga cornea on a living patient, or for cutting a donor cornea. Due to theaccuracy of the present invention's system of cutting, the presentinvention may be used for removing diseased or damaged sections of aliving patient's cornea, and then replacing these sections with similarshaped sections cut from a donor cornea.

[0125] In various aspects of performing the method of the presentinvention, the “section” of the cornea that is transplanted may be thefront portion or the rear portion of the cornea. Cutting away a sectionof the front of the cornea and replacing the excised section with adonor graft is known as “anterior lamellar keratoplasty”. Cutting away asection of the rear of the cornea and replacing the excised section witha donor graft is known as “posterior lamellar keratoplasty”.

[0126]FIG. 11 illustrates an anterior lamellar keratoplasty procedureperformed with prior art techniques; and FIG. 12 illustrates an anteriorlamellar keratoplasty procedure performed with a technique in accordancewith the present invention. FIG. 13 illustrates an posteriorkeratoplasty procedure performed with prior art techniques; and FIG. 14illustrates a posterior lamellar keratoplasty procedure performed with atechnique in accordance with the present invention. In each of FIGS. 11to 14, a cut passing through the exterior of the cornea is shown insolid lines and a cut passing only through the interior of the cornea isshown in dotted lines.

[0127] Turning first to FIG. 11, a standard anterior lamellarkeratoplasty procedure is shown. Specifically, a cut 100 is made throughcornea C such that a frontal “cap” CA of tissue is removed fortransplantation. A disadvantage of transplanting a frontal cap CA formedby cut 100 is that it s rather fragile, and prone to dislocation aftersurgery.

[0128] By instead using the present invention to form a cut 102 (FIG.12), a pocket can be made in the cornea. A particular advantage offorming a pocket by cut 102 is that the pocket will have an opening 103that is smaller than the interior width of the pocket. After the cuttingblade forms cut 102, a trephine can be used to cut straight downwardsinto cornea in a cylindrical shaped cut 104. When cut 104 reaches cut102, a cylindrical shaped portion CY of the cornea will be formed. Thiscylindrical shaped portion CY of the cornea of the donor cornea can thenbe transplanted into a similar cylindrical shaped hole cut into theliving patient's cornea. A particular advantage of transplanting such acylindrical shaped section (as opposed to transplanting a simple cap CAas shown in FIG. 11) is that a cylindrical shaped cornea sectionreceived into a cylindrical shaped hole will be much more stable andresistant to injury. Specifically, the donated corneal tissue would bemuch less likely to dislocate with vertical or lateral pressurefollowing transplantation. After healing, the donor recipient disk wouldbe much more resistant to vertical and or lateral displacement from mildtrauma than superficial corneal tissue transplanted without the physicalsupport of a rim of surrounding recipient corneal tissue.

[0129] Turning to FIG. 13, a standard posterior lamellar keratoplastyprocedure is shown. A cut 110 is made in cornea C, as shown. Cut 110does not pass fully across the cornea. Rather, a flap F of cornealtissue is formed by cut 110. After flap F is pulled back, a trephine ortrephine section is then used to cut straight downwards, thus cutting acircular shaped cut 112 forming a cylindrical shaped portion CYR of therear of the cornea.

[0130] By instead using the present invention to form a cut 120, (FIG.14) a pocket can be made in the cornea. A particular advantage offorming a pocket by cut 120 is that the pocket will have an opening 123that is smaller than the interior width of the pocket. After the cuttingblade forms cut 120, a thin profile trephine (preferably mounted on aring) or microsurgical scissors can be used to cut straight downwardsinto the deep layers of the cornea in a cylindrical shaped cut 124, thusforming a cylindrical shaped portion CYR of the rear of the cornea. Anadvantage of performing the operation in this manner is that it is notnecessary to form and pull back a “flap” of tissue from the front of thecornea. Instead, the entire operation is performed without a largeportion of the cornea being “open” to the external environment. Rather,the only opening into the cornea is through opening 123. Thisdramatically reduces the possibility for suprachoroidal hemorrhages.

[0131] In preferred aspects of the resent invention, openings 103 or 123have a width of about 4 or 5 mm and interior pockets 102 and 120 have amaximum internal diameter of about 9 or 10 mm. Cylindrical cornealsections CY and CYR typically are about 7 to 8 mm in diameter in thepatient's eye, and about 7 to 8 mm in diameter in the donor cornea.

[0132] In various aspects, the portion CYR of the donor cornea can becompletely excised with the use of microsurgical scalpels and orscissors, and portion CY can be manually separated from the superficiallayers of the cornea using microsurgical forceps.

[0133] In various aspects, viscoelastic can be injected onto the insidesurface (relative to the center of tine eyeball) of the CYR portion ofthe donor cornea to protect the corneal endothelium. The inner layer ofthe cornea is then partly folded in half with microsurgical forceps,with a cushion of viscoelastic preventing the endothelium on each halfof the donor disk CYR from touching together. Viscoelastic can also beused to position the donor corneal disk into the space previouslyoccupied by the excised recipient corneal disk CYR.

[0134] The opening 103 or 123 of the corneal pocket may optionally beclosed with sutures or tissue glue to make the wound water tight.Possible tissue glues which could be used include cyanoacrylate,fibrinogen tissue adhesives, or dendrimers. Viscoelastic can be removedfrom the anterior chamber using irrigation of balanced salt solution andaspiration.

[0135] It is to be understood that the dimensions for the size and shapeof cuts made in the recipient and donor corneal tissues are merelyrepresentative of the type of surgery which can be done. Thus,variations in the dimensions and shape of the pocket, flap, cap, andcorneal donor or recipient disks are expected, all keeping within thescope of the present invention.

[0136] Referring to FIG. 15A a top view of a mechanical system foroscillating moveable member 210 along non-linear path O around pivotelement 214. Specifically, FIG. 15A shows moveable member 210 at a firstposition (shown in solid lines) and moveable member 210 in a secondposition (shown in dotted lines). Moveable member 210 is moved from thefirst position to the second position along a non-linear path O, by themovement of restraining element 221 within hollow slot 216 in a cuttingguide restraint 222. Restraining element 221 in this embodiment is aprotrusion, but in alternative embodiments may be a hole designed toreceive a protrusion. In preferred aspects, restraining element 221 ismounted eccentrically on a wheel 235 which is connected to aprogrammable oscillating motor 232 (FIG. 15B) such as a stepper or servomotor. The programmable oscillating motor turns wheel 235 around pivotelement 215 in direction O′. In this embodiment, the cutting guidecomprises a software program which limits the angular motion ofprogrammable oscillating motor 232. Programmable oscillating motor 232is engaged to cutting guide restraint 216 by restraining element 221.The cutting guide software program thereby limits the degree of angularmovement of cutting element 212 around pivot element 214. Cuttingelement 212 may be a solid cutting blade, but may also be any othercutting mechanism appropriate to cut the cornea e.g. electromagneticenergy such as a laser or plasma field. In alternate preferred aspects,cutting element 212 is deformable in shape and size, such as in the caseof a sharp wire loop that can be extended or retracted to increase ordecrease the cutting surface. The deformability of the bladeadvantageously allows the size of the blade to increase once it isbeyond the entry incision which helps to enable the creation of a largepocket through a small incision.

[0137]FIG. 15B illustrates a side view of the above described mechanicalsystem. Restraining element 221 is located within a hollow slot 216(shown in dotted lines) of the cutting guide restraint 222. Whenprogrammable oscillating motor 232 turns wheel 235, moveable member 210pivots around pivot element 214. In preferred aspects, the movements ofthe programmable oscillating motor are controlled by a cutting guide(software program) encoded within encoder 237 or computer 238. In oneembodiment, the cutting mechanism including moveable arm 210, cuttingelement 212, pivot element 214, cutting guide restraint 216, wheel 234,and programmable oscillating motor 232 are all mounted on a platform242. The cutting mechanism components can be driven forward by aprogrammable drive motor 239. In preferred aspects, when programmabledrive motor 239 turns a lead screw 275 that is engaged to threads 244 onplatform 242, the platform and the cutting mechanism will move forwardor back. Alternative methods of moving the cutting mechanism forward andback (e.g. with motors, pneumatics, and the like) can also be used andare all within the scope of the described invention. In preferredaspects, movements of the programmable drive motor 239 are controlled bythe cutting pattern guide software program that is encoded withinencoder 237 and/or computer 238.

[0138]FIG. 16 illustrates an embodiment where the cutting pattern guidecomprises a software program that controls the movements of aprogrammable oscillating motor (not shown) and a programmable drivemotor (not shown). The programmable oscillating motor is connected towheel 235. The angular movement Θ₂ of blade 212, moveable member 210,and cutting guide restraint 216 around pivot point 214 is controlled bythe movement of restraining element 221 within hollow slot 216 ofcutting guide restraint 222. Restraining element 221 is mounted on wheel235 of radius R which rotates around center point 215. When wheel 235rotates, an angle Θ₁ is formed between the X axis and the line throughpivot point 215 and restraining element 221. The distance between pivotpoint 214 and center point 215 is L. Using trigonometry the relationshipbetween an angle Θ₂ and Θ₁ can be determined. The cutting guide softwareprogram thereby controls the path of the cut into cornea C bycontrolling the rotation of wheel 235 through the programmableoscillating motor and the movement of the moveable member along theX-axis through the programmable drive motor. Please note, during thecreation of the pocket P through incision I, cornea C is temporarilyflattened by the use of an applanator (not shown). The cornea C may bepart of a living eyeball or may be a donor cornea that has been excisedfrom a cadaveric (donor) eyeball.

[0139] As shown in FIG. 17, if the position of pivot point 214 isadjustable in both the X axis and the Y axis, such additional freedom ofmovement allows the cutting element to create a relatively large pocketP′ through a small external opening I. Specifically the maximal width Wof pocket P′ may be more than twice the width of incision I. Theinternal boundary B of Pocket P′ is shown in dotted lines. In this FIG.17, width of entry incision I is 4 mm and the maximum width W of pocketP′ is 10 mm. This can be created with a 2 mm wide blade 12, with amoveable member 10 of 1 mm width, and a pivot element 214 which is 12 mmbehind the tip of the cutting element 212.

[0140] In the embodiment of FIG. 17, the position of pivot point 214 ismade adjustable by mounting pivot point 214 on a wheel 237. Wheel 237turns around pivot point 215. Restraining element 221 is mounted on agear G′ and is located within hollow slot 216 cutting guide restraint222. Gear G′ is concentric to wheel 237 and is also centered on pivot215. Moveable member 210 and cutting guide restraint 222 are shown indotted lines to indicate that they are beneath wheel 37 and gear G′.Gear G′ is rotated by a second gear (not shown) that is engaged to aprogrammable motor (not shown). The angles of the cutting element 212,moveable member 210, and cutting restraint 216 are determined by therelative positions of pivot point 214 and restraining element 221. Thepositions of pivot point 214 and restraining element 221 are determinedby two separate programmable motors (not shown) which control therotational angles of wheel 37 and gear G′. Angle Θ₃ represents the anglebetween the X-axis and the line drawn through pivot point 214 and centerpoint 215 and the X axis. Angle Θ₄ represents the angle between theX-axis and the line drawn through restraining element 221 and centerpoint 215. Angle Θ₅ represents the angle between the X-axis and the linedrawn through restraining element 221 and pivot point 214. Angle Θ₅ alsorepresents the angle between the cutting element 212 and the X axis. Inorder to create a pocket within the cornea, cutting element 212,moveable member 210, cutting restraint 222, wheel 237 are all movedtoward cornea C along the X axis by a programmable drive motor (notshown), while the positions of the pivot point 214 and restrainingelement 221 are determined by programmable motors that are controlled bycutting guide software.

[0141] Table I shows a sample set of parameters for D′, Θ₅, Θ₃, Θ₄ thatcan be used to cut a pocket within the cornea which has a 4 mm entryincision I and an internal width W of 10 mm. The blade 12 is 2 mm widewith a moveable member 10 of 1 mm width, and a pivot element 14 which is12 mm behind the tip of the cutting blade 12. Positive values indicateclockwise rotation from the X-axis. Negative values indicatedcounterclockwise rotation from the X-axis. The following parameters canbe incorporated into cutting guide software that controls programmablemotors.

[0142] The cutting path derived from the parameters in Table I is shownin FIGS. 18A-18D [CONFIRM]. For each distance D′ of pivot point 215 awayfrom cornea C, the positions of blade 212, pivot element 214, andrestraining element 221 are shown in relation to pocket P′ and incision1. TABLE 1 Angle of Distance of Center Restraining of Wheel from theAngle of Blade Angle of Pivot Element Cornea D′ in degrees θ₅ in degreesθ₃ in degrees θ₄ 19 0 0 0 19 −5 0 −9 19 0 0 0 19 +5 0 +9 18 0 0 0 18 −50 −9 18 0 0 0 18 +5 0 +9 17 0 0 0 17 −5 0 −9 17 0 0 0 17 +5 0 +9 16 0 00 16 −5 0 −9 16 0 0 0 16 +5 0 +9 15 0 0 0 15 −5 0 −9 15 0 0 0 15 +5 0 +914 0 0 0 14 +30 −34 +65 14 0 0 0 14 −30 +34 −65 13 0 0 0 13 −30 +24 −7113 0 0 0 13 +30 −24 +71 12 0 0 0 12 +37 −22 +73 12 0 0 0 12 −37 +22 −7311 0 0 0 11 −35 +18 −68 11 0 0 0 11 +35 −18 +68 10 0 0 0 10 +20 −8 +3910 0 0 0 10 −20 +8 −39 9.5 0 0 0 9.5 −5 0 −9 9.5 0 0 0 9.5 +5 0 +9 9.5 00 0

[0143] An alternative embodiment is shown in FIG. 19 where the pivotpoint 214 is mounted on a platform 247 and restraining element 221 ismounted on platform 243. Gear G rotates around center point 215 and gearG″ rotates around center point 217. The rotation of gears G and G″determines the angle of blade 212 relative to axis A. Through the use oftrigonometry, a table can be created and then used to program thecutting guide software to create a corneal pocket. Combinations ofrotatable wheels and platforms that move along linear paths may also beused to position pivot point 214 and restraining element 221.

[0144] Another way that a relatively large pocket can be made through asmall incision is to fixate pivot point 214 relative to the cornea, butto allow the moveable member 210 to translate and rotate over or underthe pivot point 214. FIGS. 20A-20D show the moveable member 210translating and rotating over or under pivot point 214 to allow cuttingelement 212 to create a relatively large pocket P′ through a smallincision I′. Usually, the mechanism (not shown) to translate or rotatethe moveable member 210 over or under pivot point 214 will be mounted ontranslatable or otherwise positionable table to allow axial movement ofthe moveable member 210 relative to the cornea (not shown).

[0145] An example of a cutting mechanism that does not contain a pivotelement is shown in FIG. 21. Moveable member 210 is shown having twocutting guide restraints on each side, e.g., protrusions 218. Wires 220are attached to protrusions 218 and programmable motors 233 that caneither wind the wires to a shorter length or unwind the wires to alonger length. The programmable motors are controlled by cutting guidesoftware. The winding and unwinding of the wires 220 applies force tothe moveable member in the directions of the arrows adjacent to thewires and move the moveable member in an angular or translational way tocreate a cut by cutting element 212. In this embodiment, force isapplied via wires, but any form of mechanical, pneumatic, electrical, ormagnetic force could be used to create the same effect.

[0146]FIGS. 23A and 23B show an alternate embodiment of the presentinvention in which an applanator 254 is only slightly larger than thecutting element 212 and moveable member 210. In FIGS. 23C-23F Applanator254 is shown in solid lines overlying the cornea C. Blade 212 andmoveable member 210 are shown in dashed lines moving within pocket P.Applantor 254 moves concurrently with moveable member 210 and blade 212to flatten cornea C in advance of blade 212 and moveable member 210.

[0147]FIGS. 23A and 23B also show an optional anterior chambermaintainer 60 that may be used as an attachment to the presentembodiment. Details of the anterior chamber maintainer 60 werepreviously shown in FIGS. 7A and 8B. Anterior chamber maintainer 60 isspecifically used when cutting tissue in a donor cornea. The donorcorneal tissue is usually provided to the surgeon in the form of anexcised cornea with a small rim of surrounding scleral tissue. As statedabove, the present invention is designed to cut the cornea of a livingcomplete eyeball. However, in order to harvest a donor cornea, it isalso necessary to have an apparatus that will also enable the inventionto cut a donated cornea that has been excised from the donor eyeball.The use of anterior chamber maintainers with prior art pocket formingdevices has not been described. However, anterior chamber maintainers ofthe present invention may be adapted for use with other pocket formingdevices such as such as those described by Peyman in U.S. patentapplication Ser. No. 20010004702 and Feingold in U.S. Pat. No. 6,599,305to allow harvesting of donor corneal tissue. The anterior chambermaintainer may be used for harvesting a donor cornea for any pocketforming device that requires stabilization of the donor cornea duringthe pocket forming process

[0148] The sizes, distances, positions, and angles of the components ofthe present embodiments are merely representative of the types ofmechanical devices and software which can be created. It is to beexpected that other sizes, distances, positions, and angles ofcomponents can be used, all of which are in keeping within the scope ofthe present invention. Although, the described embodiments of theinvention describe primarily non-manual methods of translating androtating the cutting element, it is to be understood that manualtranslation and rotation of the cutting element is also within the scopeof the invention.

[0149] The present invention provides a method for creating a cornealpocket that may have a small external incision and a relatively largepocket. The corneal pocket created by the present invention may beadvantageously used to retain an intracorneal lens that is reversiblydeformable in shape. Once the lens is within the pocket, the smallexternal opening prevents inadvertent dislocation or extrusion. FIG. 24A shows a cross-section of a human eyeball which shows the relativelocation of cornea C. FIG. 24B shows a cross-sectional view of thecornea with a pocket 330 shown in broken lines and a small externalopening 333. FIG. 37C shows a cross-sectional view of the cornea with alens implant 334 within the pocket. The reversibly deformable lens maybe folded or squeezed to allow entry through opening 333. The deformablelens may also be composed of a thermally reactive polymer that allowsthe implant to be in a shape that easily fits through opening 333 atroom temperature (e.g. a rod) and then allows the implant to change intoa final well fitting shape (e.g. a disk) when it is exposed to bodytemperature (not shown). Once the deformable lens is implanted intopocket 330, small external opening 333 may spontaneously self seal.Alternatively small external opening 333 can be closed with sutures ortissue adhesives.

[0150] Comparison between the pocket size achievable with the presentinvention and that achievable with a prior art device is shown in FIGS.22A-22B. A prior art corneal cutting device by Feingold is shown in FIG.22A. In this apparatus, the blade assembly 240 oscillates the blade 244laterally via blade assembly stem 242 while extending forward into thecornea to form the pocket P″, and the amplitude of the lateraloscillation increases as the blade goes beyond an entry incision I′ intothe cornea C. The inner dotted lines indicate the boundary of pocket P″.The outer dotted lines B′ indicate the boundary of a pocket created bythe present invention. As shown in FIG. 22B, the smallest theoreticalpossible size of the entry incision would be the maximal width BW of thecutting blade 244. This type of entry incision would be created in thecase that the blade 244 does not oscillate laterally during the entrycut. In this FIG. 22B the width BW of the blade is the same size asincision I′.

[0151] Once the blade is inside of the cornea as shown in FIG. 22C, thelimit of lateral travel of the blade is governed by the width of theentry incision I′ and the width of the blade assembly stem 242 thatmoves the blade. The stem of the blade assembly may not move morelateral than the lateral limit of the entry incision I′ . When the blademoves to the right, the width of the pocket is extended to the right onehalf of the maximal width of the blade BW minus one half the width ofthe blade assembly stem 242.

[0152] When the blade moves to the left as shown in FIG. 22D, the widthof the pocket is extended to the left one half of the maximal width ofthe blade BW minus one half the width of the blade assembly stem 242.Therefore, the maximal width of the pocket W′ is twice the maximal widthof the blade minus the width of the blade assembly stem. The inner setof dotted lines F is the boundary of the pocket that can be created withFeingold's device. In the case that the width of the stem of the bladeassembly approaches zero (not shown), the maximum width of the pocket issimply twice the blade width. Therefore, if the minimum width of theentry incision is the width of the blade and the maximum width of thepocket can only be twice the width of the blade, the ratio of themaximum pocket width to the entry incision width will always be lessthan the number two. From a practical standpoint, the ratio of themaximum pocket width to the entry incision will be significantly lessthan two because the blade assembly will usually need to oscillate tocreate the entry incision and the stem of the blade assembly cannot bezero. In this scaled drawing the maximal width of pocket P″ is equal to7 mm, the width of the incision I′ is equal to 4 mm and the blade widthBW is also equal to 4 mm. The ratio of the maximum pocket width W′ tothe incision width I′ in this case is 1.75. The boundary B′ is theboundary of a pocket using the present invention. Note that boundary B′is larger than boundary F for the same size incision I. The width of Win this scaled drawing is 10 mm and the incision width 1 is 4 mm. Pleasealso note that the ratio of the width of the pocket for the presentinvention W to the width of I′ is 2.5, which is greater than the numbertwo.

[0153] While the above is a complete description of the preferredembodiments of the invention, various alternatives, modifications, andequivalents may be used. Therefore, the above description should not betaken as limiting the scope of the invention which is defined by theappended claims.

What is claimed is:
 1. A system for cutting the cornea of an eye, saidsystem comprising: a frame which can be immobilized relative to thecornea; a moveable member having a cutting element at a distal end; anda driver coupled to the moveable member, said driver adapted to bothtranslate and rotate the moveable member relative to the frame.
 2. Asystem as in claim 1, wherein the frame comprises a suction ring.
 3. Asystem as in claim 1, wherein the system further comprises a cornealapplanator.
 4. A system as in claim 1, wherein the moveable member islinear.
 5. A system as in claim 1, wherein the moveable member isnon-linear.
 6. A system as in any one of claims 1 to 5 or 49, whereinthe moveable member rotates on a pivot.
 7. A system as in claim 6,further comprising a path upon which the pivot can translate.
 8. Asystem as in claim 7, wherein the path is linear and disposed along anaxis aligned with a center of the cornea when the cornea is immobilizedrelative to the frame.
 9. A system as in claim 7, wherein the path isnon-linear.
 10. A system as in claim 6, wherein the pivot is fixedrelative to the frame and the moveable member is adapted to translateand rotate over or under the pivot.
 11. A system as in claim 10, whereinthe pivot comprises a protrusion.
 12. A system as in claim 10, whereinthe pivot comprises lateral restraints.
 13. A system as in claim 6,wherein the pivot is selectively positionable over a two-dimensionalplane.
 14. A system as in any one of claims 1 to 5 or 49, wherein themoveable member is selectively positionable in a two-dimensional planewithout a pivot.
 15. A system as in claim 1, wherein the moveable memberis adapted to be manually translated and rotated.
 16. A system as inclaim 15, further comprising a template for limiting manual movement ofthe moveable member.
 17. A system as in claim 1, further comprising amotor assembly for translating and rotating the moveable member.
 18. Asystem as in claim 17, further comprising a programmable controller forcontrolling the motor to manipulate the moveable arm in a programmedpattern.
 19. A system as in claim 18, wherein the programmablecontroller comprises a digital processor.
 20. A system as in any one ofclaim 1 to 5 or 49, further comprising an anterior chamber maintainerwhich can be used in place of the frame for supporting a donor corneawhile being cut by the blade of the moveable member.
 21. A method forcutting a pocket in a cornea, said method comprising: advancing acutting element at the distal end of a moveable member through an entryincision into the cornea; and controlling movement of the moveablemember to cause the cutting element to create a pocket having a width inat least one direction through the center of the cornea, which isgreater than twice a width of the entry incision.
 22. A method as inclaim 21, wherein the width of the entry incision is no greater than 4mm and the width of the pocket is greater than 8 mm.
 23. A method as inclaim 22, wherein the width of the pocket is at least 10 mm.
 24. Amethod as in claim 21, wherein the width of the pocket is at least 8 mm.25. A method as in any one of claims 21 to 24 or 50, wherein themoveable member has a width no greater than 1 mm in a region where themember passes through the entry incision.
 26. A method as in claim 21,wherein controlling comprises both translating and rotating the moveablemember relative to the cornea.
 27. A method as in claim 26, wherein themoveable member is rotated relative to a pivot point and the pivot pointis translated relative to the cornea.
 28. A method as in claim 26,wherein the moveable member is translated over or under a pivot pointand the pivot point is fixed relative to the cornea.
 29. A method as inany one of claims 21 to 24 or 50, further comprising implanting a lensin the pocket.
 30. A method as in claim 29, wherein the lens isrestrained in a reduced profile configuration while being implanted. 31.A method as in any one of claims 21 to 24 or 50, further comprisingimplanting a corneal graft in the pocket.
 32. A method for cutting apocket in a cornea, said method comprising: advancing a cutting elementat the distal end of a moveable member through an entry incision intothe cornea; and controlling movement of the moveable member to cause thecutting element to create the pocket, wherein the moveable member isboth rotated and translated relative to the cornea.
 33. A method as inclaim 32, wherein the moveable member is rotated relative to a pivotpoint and the pivot point is translated relative to the cornea.
 34. Amethod as in claim 32, wherein the moveable member is translated over apivot point and the pivot point is fixed relative to the cornea.
 35. Amethod as in claim 32, wherein the width of the entry incision is nogreater than 4 mm and movement of moveable member is controlled tocreate a pocket having a width greater than 8 mm.
 36. A method as inclaim 35, wherein the width of the pocket is at least 10 mm.
 37. Amethod as in claim 36, wherein the width of the pocket is at least 8 mm.38. A method as in claim 35, wherein the moveable member has a width nogreater than 1 mm in a region where the member passes through the entryincision.
 39. A method as in any one of claims 32 to 38, furthercomprising implanting a lens in the pocket.
 40. A method as in claim 34,wherein the lens is restrained in a reduced profile configuration whilebeing implanted.
 41. A method as in any one of claims 32 to 38, furthercomprising implanting a corneal graft in the pocket.
 42. A method fortransplanting a cornea, said method comprising: creating a pocket in thecornea of a patient, said pocket having an entry incision with a widthless than that of the pocket; removing a cylinder of tissue from over orunder the pocket while the remaining portions of the corneal tissueremain intact to limit exposure of the interior of the eye toatmospheric pressure, replacing the removed cylinder of tissue withdonor tissue.
 43. A method as in claim 42, wherein tissue over thepocket is removed and replaced to perform an anterior lamellarkeratoplasty.
 44. A method as in claim 42, wherein tissue beneath thepocket is removed and replaced to perform a posterior lamellarkeratoplasty.
 45. A method as in claim 42, wherein the pocket is createdby advancing a blade into the cornea while flattening the cornea with anapplanator.
 46. A method as in claim 42, further comprising harvestingthe donor tissue with the same pocket making device that was used tocreate a pocket in the recipient cornea.
 47. A method as in claim 46,wherein the donor cornea is supported on an anterior chamber maintainerwhile the donor cornea is cut with the cutting element.
 48. A system forharvesting a donor cornea, said system comprising an anterior chambermaintainer adapted to support the donor cornea while a pocket formingdevice creates a pocket within the donor cornea.
 49. A system as inclaim 1, wherein the cutting element is deformable.
 50. A method as inclaim 1, further comprising deforming the cutting element to reduce itsprofile while the cutting element is advanced through the entryincision.